Solar Impulse 2 Flies New Materials

The second version of the 100% solar-powered airplane, Solar Impulse, has been completed. It debuted April 9 in Payerne, Switzerland. The new airplane will be the one used in next year's attempted around-the-world flight.

Last year, the first prototype model of the Solar Impulse plane completed a piloted, cross-country flight over the US from California to New York. The new Solar Impulse 2 model will undergo several test flights during 2014 before its big flight in March 2015.

The new plane will be powered by about 17,200 solar cells on the wings, about 50% more than the first version. Made of lightweight materials, the entire aircraft weighs 2.3 metric tons (2,300 kg), nearly 50% more than Solar Impulse 1. Its wingspan is 72 meters (236 feet), slightly larger than its first incarnation and about the same as the largest passenger airliner. Several of its materials have been designed by Bayer MaterialScience and Solvay. You can watch the official presentation video (over three hours) here, and a 20-minute walk-around video with closeups and descriptions of the plane here.

Click on the image below for a closer look at the Solar Impulse 2.

Aboard the Solar Impulse 2 are several advanced materials from Bayer MaterialScience, which has been an official sponsor of the project since 2010. The company was responsible for the design of the entire cockpit shell and for providing materials for other structural components and films for the cabin window.
(Source: Bayer MaterialScience)

Solvay says its contributions include the Halar ECTFE ultra-thin polymer film that protects the solar panels and solar cells against moisture, the Solstick PVDF Solef adhesive tape closing gaps between solar cells, and PVDF Solef and F1EC solvent for protecting the plane's 640 kg of lithium-ion batteries and for improving energy density. The batteries, recharged during the day by the solar cells, will allow the plane to fly at night.

Other Solvay materials include Fomblin PFPE lubricant for mechanical parts; strong and lightweight materials, such as specialty polymers Ketaspire PEEK and PrimoSpire SRP for fasteners and screws; and Polyamide 6 Sinterline for 3D-printing complex mechanical parts, such as lighting clips or the housings for cockpit equipment, using selective laser sintering (SLS). The wings' carbon-fiber honeycomb sandwich structure, which helps the plane stay lightweight and strong, is made with paper impregnated by Solvay's TorlonPAI polymer.

Both planes are heavy users of materials from Bayer MaterialScience. In the first model these included high-performance polyurethane foams in the cabin, motor gondolas, and wing tips, and also highly transparent polycarbonate and films in the cabin window and other locations. The cockpit insulating material is a high-performance insulating Baytherm Microcell foam, according to a press release. This material is also used in the aircraft door. The rest of the cockpit shell is made with a different type of polyurethane rigid foam. Bayer was responsible for designing the Solar Impulse 2's entire cockpit shell.

A Bayer rigid polyurethane foam is also used to insulate the batteries. A polyurethane/carbon-fiber composite material is used for door locks, and the window is made of high-performance polycarbonate. The silver-colored coating that covers large areas of the plane's exterior and the adhesives that keep the wings' fabric attached are also made of raw materials from Bayer.

Bayer says it expects to use the "flying laboratory" of Solar Impulse planes to help develop its existing products and test new ones. A few days before the Solar Impulse 2's unveiling, Bayer announced an integrated cockpit design concept for automotive interiors based on polycarbonate.

The Solar Impulse project began in 2003. The first test flights began in 2009. The first aircraft completed test flights within Europe and to North Africa while construction began on the slightly larger Solar Impulse 2. The total in-air flight time in 2015 is expected to be 20 days, but breaks to relieve the pilot will make the entire journey last about three months.

I know exactly what you mean, Ann. I remember way back in the early days of my career about 15 years ago I would complain that companies had a hard time putting basic information like location and contact info in an obvious spot on the website. And it seems they still even do that today, when websites and ready access to information are so ubiquitous. The mind boggles. I bet the people designing these sites are being paid a lot more than me, too! ;)

That's not only one of my pet peeves as a journalist, it's among the top 3. Unfortunately, there is no industry-wide "institutional memory" about media relations (as there was for a time in electronics & semiconductors) for each new company to learn from. And even startups in Silicon Valley repeat the same mistakes anew.

That is one of my top pet peeves as a journalist, Ann. Companies and projects today still dont' seem to know how to engage properly with a press audience. You think by now they would know even how to communicate the basic information people need. But I still find myself baffled by websites and their lack of ease of use sometimes.

The website may be fun for a casual viewer to get lost in, or someone who only wants the latest news, but for a reporter or anyone else trying to get info like a timeline or details of specific events, it's quite frustrating.

You're right, I have seen lots of coverage. I guess they don't need a good website if everyone else is giving them a good media presence. It is a really interesting project and definitely worthy of all the attention.

Thanks for sharing your knowledge and expertise tekochip. I knew about oxygen masks, but not that small planes like a Cessna can be pressurized. Considering the weight penalties you cite, I'd guess SI 2 must be using masks.

Here in The States, the FAA requires supplemental oxygen above 12,500 for more than 30 minutes, or at any time above 14,000. If the cabin is pressurized you need to have an emergency supply available but I won't quote the all of the FARs here.

Bottled oxygen, masks and cannulas are sold at pilot shops and many General Aviation airports can refill bottles on site. A 50 cubic foot cylinder will last a little over 40 hours. I don't know about the Solar Impulse, but even something as small as the Cessna 210 is available pressurized. For the average General Aviation owner, a pressurized aircraft adds a great deal of extra cost and complexity, while losing performance.

Many of the new adhesives we're featuring in this slideshow are for use in automotive and other transportation applications. The rest of these new products are for a wide variety of applications including aviation, aerospace, electrical motors, electronics, industrial, and semiconductors.

A Columbia University team working on molecular-scale nano-robots with moving parts has run into wear-and-tear issues. They've become the first team to observe in detail and quantify this process, and are devising coping strategies by observing how living cells prevent aging.

Many of the new materials on display at MD&M West were developed to be strong, tough replacements for metal parts in different kinds of medical equipment: IV poles, connectors for medical devices, medical device trays, and torque-applying instruments for orthopedic surgery. Others are made for close contact with patients.

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.